﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;

namespace CameraC
{
    using System;
    using System.Runtime.InteropServices;
    namespace webcam
    {
        /**////
            /// avicap 的摘要说明。
            /// 
        public class showVideo
        {
            // showVideo calls
            [DllImport("avicap32.dll")]
            public static extern IntPtr capCreateCaptureWindowA(byte[] lpszWindowName, int dwStyle, int x, int y, int nWidth, int nHeight, IntPtr hWndParent, int nID);
            [DllImport("avicap32.dll")]
            public static extern bool capGetDriverDescriptionA(short wDriver, byte[] lpszName, int cbName, byte[] lpszVer, int cbVer);
            [DllImport("User32.dll")]
            public static extern bool SendMessage(IntPtr hWnd, int wMsg, bool wParam, int lParam);
            [DllImport("User32.dll")]
            public static extern bool SendMessage(IntPtr hWnd, int wMsg, short wParam, int lParam);
            [DllImport("User32.dll")]
            public static extern bool SendMessage(IntPtr hWnd, int wMsg, short wParam, FrameEventHandler lParam);
            [DllImport("User32.dll")]
            public static extern bool SendMessage(IntPtr hWnd, int wMsg, int wParam, ref BITMAPINFO lParam);
            [DllImport("User32.dll")]
            public static extern int SetWindowPos(IntPtr hWnd, int hWndInsertAfter, int x, int y, int cx, int cy, int wFlags);
            [DllImport("avicap32.dll")]
            public static extern int capGetVideoFormat(IntPtr hWnd, IntPtr psVideoFormat, int wSize);
            // Constants
            public const int WM_USER = 0x400;
            public const int WS_CHILD = 0x40000000;
            public const int WS_VISIBLE = 0x10000000;
            public const int SWP_NOMOVE = 0x2;
            public const int SWP_NOZORDER = 0x4;
            public const int WM_CAP_DRIVER_CONNECT = WM_USER + 10;
            public const int WM_CAP_DRIVER_DISCONNECT = WM_USER + 11;
            public const int WM_CAP_SET_CALLBACK_FRAME = WM_USER + 5;
            public const int WM_CAP_SET_PREVIEW = WM_USER + 50;
            public const int WM_CAP_SET_PREVIEWRATE = WM_USER + 52;
            public const int WM_CAP_SET_VIDEOFORMAT = WM_USER + 45;
            // Structures
            [StructLayout(LayoutKind.Sequential)]
            public struct VIDEOHDR
            {
                [MarshalAs(UnmanagedType.I4)]
                public int lpData;
                [MarshalAs(UnmanagedType.I4)]
                public int dwBufferLength;
                [MarshalAs(UnmanagedType.I4)]
                public int dwBytesUsed;
                [MarshalAs(UnmanagedType.I4)]
                public int dwTimeCaptured;
                [MarshalAs(UnmanagedType.I4)]
                public int dwUser;
                [MarshalAs(UnmanagedType.I4)]
                public int dwFlags;
                [MarshalAs(UnmanagedType.ByValArray, SizeConst = 4)]
                public int[] dwReserved;
            }
            [StructLayout(LayoutKind.Sequential)]
            public struct BITMAPINFOHEADER
            {
                [MarshalAs(UnmanagedType.I4)]
                public Int32 biSize;
                [MarshalAs(UnmanagedType.I4)]
                public Int32 biWidth;
                [MarshalAs(UnmanagedType.I4)]
                public Int32 biHeight;
                [MarshalAs(UnmanagedType.I2)]
                public short biPlanes;
                [MarshalAs(UnmanagedType.I2)]
                public short biBitCount;
                [MarshalAs(UnmanagedType.I4)]
                public Int32 biCompression;
                [MarshalAs(UnmanagedType.I4)]
                public Int32 biSizeImage;
                [MarshalAs(UnmanagedType.I4)]
                public Int32 biXPelsPerMeter;
                [MarshalAs(UnmanagedType.I4)]
                public Int32 biYPelsPerMeter;
                [MarshalAs(UnmanagedType.I4)]
                public Int32 biClrUsed;
                [MarshalAs(UnmanagedType.I4)]
                public Int32 biClrImportant;
            }
            [StructLayout(LayoutKind.Sequential)]
            public struct BITMAPINFO
            {
                [MarshalAs(UnmanagedType.Struct, SizeConst = 40)]
                public BITMAPINFOHEADER bmiHeader;
                [MarshalAs(UnmanagedType.ByValArray, SizeConst = 1024)]
                public Int32[] bmiColors;
            }
            public delegate void FrameEventHandler(IntPtr lwnd, IntPtr lpVHdr);
            // Public methods
            public static object GetStructure(IntPtr ptr, ValueType structure)
            {
                return Marshal.PtrToStructure(ptr, structure.GetType());
            }
            public static object GetStructure(int ptr, ValueType structure)
            {
                return GetStructure(new IntPtr(ptr), structure);
            }
            public static void Copy(IntPtr ptr, byte[] data)
            {
                Marshal.Copy(ptr, data, 0, data.Length);
            }
            public static void Copy(int ptr, byte[] data)
            {
                Copy(new IntPtr(ptr), data);
            }
            public static int SizeOf(object structure)
            {
                return Marshal.SizeOf(structure);
            }
        }
        //Web Camera Class
        public class WebCamera
        {
            // Constructur
            public WebCamera(IntPtr handle, int width, int height)
            {
                mControlPtr = handle;
                mWidth = width;
                mHeight = height;
            }
            public delegate void RecievedFrameEventHandler(byte[] data);
            public event RecievedFrameEventHandler RecievedFrame;
            private IntPtr lwndC; // Holds the unmanaged handle of the control
            private IntPtr mControlPtr; // Holds the managed pointer of the control
            private int mWidth;
            private int mHeight;
            private showVideo.FrameEventHandler mFrameEventHandler; // Delegate instance for the frame callback - must keep alive! gc should NOT collect it
                                                                    // Close the web camera
            public void CloseWebcam()
            {
                this.capDriverDisconnect(this.lwndC);
            }
            // start the web camera
            public void StartWebCam()
            {
                byte[] lpszName = new byte[100];
                byte[] lpszVer = new byte[100];
                showVideo.capGetDriverDescriptionA(0, lpszName, 100, lpszVer, 100);
                this.lwndC = showVideo.capCreateCaptureWindowA(lpszName, showVideo.WS_VISIBLE + showVideo.WS_CHILD, 0, 0, mWidth, mHeight, mControlPtr, 0);
                if (this.capDriverConnect(this.lwndC, 0))
                {
                    this.capPreviewRate(this.lwndC, 66);
                    this.capPreview(this.lwndC, true);
                    showVideo.BITMAPINFO bitmapinfo = new showVideo.BITMAPINFO();
                    bitmapinfo.bmiHeader.biSize = showVideo.SizeOf(bitmapinfo.bmiHeader);
                    bitmapinfo.bmiHeader.biWidth = 352;
                    bitmapinfo.bmiHeader.biHeight = 288;
                    bitmapinfo.bmiHeader.biPlanes = 1;
                    bitmapinfo.bmiHeader.biBitCount = 24;
                    this.capSetVideoFormat(this.lwndC, ref bitmapinfo, showVideo.SizeOf(bitmapinfo));
                    this.mFrameEventHandler = new showVideo.FrameEventHandler(FrameCallBack);
                    this.capSetCallbackOnFrame(this.lwndC, this.mFrameEventHandler);
                    showVideo.SetWindowPos(this.lwndC, 0, 0, 0, mWidth, mHeight, 6);
                }
            }
            // private functions
            private bool capDriverConnect(IntPtr lwnd, short i)
            {
                return showVideo.SendMessage(lwnd, showVideo.WM_CAP_DRIVER_CONNECT, i, 0);
            }
            private bool capDriverDisconnect(IntPtr lwnd)
            {
                return showVideo.SendMessage(lwnd, showVideo.WM_CAP_DRIVER_DISCONNECT, 0, 0);
            }
            private bool capPreview(IntPtr lwnd, bool f)
            {
                return showVideo.SendMessage(lwnd, showVideo.WM_CAP_SET_PREVIEW, f, 0);
            }
            private bool capPreviewRate(IntPtr lwnd, short wMS)
            {
                return showVideo.SendMessage(lwnd, showVideo.WM_CAP_SET_PREVIEWRATE, wMS, 0);
            }
            private bool capSetCallbackOnFrame(IntPtr lwnd, showVideo.FrameEventHandler lpProc)
            {
                return showVideo.SendMessage(lwnd, showVideo.WM_CAP_SET_CALLBACK_FRAME, 0, lpProc);
            }
            private bool capSetVideoFormat(IntPtr hCapWnd, ref showVideo.BITMAPINFO BmpFormat, int CapFormatSize)
            {
                return showVideo.SendMessage(hCapWnd, showVideo.WM_CAP_SET_VIDEOFORMAT, CapFormatSize, ref BmpFormat);
            }
            private void FrameCallBack(IntPtr lwnd, IntPtr lpVHdr)
            {
                showVideo.VIDEOHDR videoHeader = new showVideo.VIDEOHDR();
                byte[] VideoData;
                videoHeader = (showVideo.VIDEOHDR)showVideo.GetStructure(lpVHdr, videoHeader);
                VideoData = new byte[videoHeader.dwBytesUsed];
                showVideo.Copy(videoHeader.lpData, VideoData);
                if (this.RecievedFrame != null)
                    this.RecievedFrame(VideoData);
            }
        }
    }
}

    

